Signaling system.



C. E. BEACH.

SIGNALING SYSTEM.

APPLICATION FILED MAI/Is, |914.

Patented A131113, 1915.

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CLARENCE E. BEACH, 0F BINGHAM'ION, NEW YORK, ASSXGNB, TO GEORGE O.KNAPP, 0F NEW YQRK, N. 'SZ'.

SIGNALING SYSTEM. i '1 f Application filed May 18, 1914.-.

T0 all whom it may concern Be it known that I, CLARENCE E. BEACH, acitizen of the United States, residing at Binghamton, in the county ofBroome and State oit New York, have invented certain new and usefulimprovements in Signaling Systems, ci which the following is aspecication.

My invention relates to signaling1 systems and particularly to systemsin which the line wires are maintained under constant test for theircontinuity by the use of a minimum amount of energy, and having meanswhereby the flow of current through the receiving devices will begreatly increased during the transmission of a signal.

din object of my invention is to provide such a system in which aplurality of transmitting devices are so a 1ranged in a simple seriescircuit that their contacts merely control a weak current.

Another object of my invention is to provide means whereby a constanttest for ground (or leakage from the line wires to ground) may bemaintained without thereby rendering it possible to so shunt any of' thereceiving devices as to prevent their acting to transmit an alarm, andat the same time minimize the chance of disabling any ot the alarmtransmitting devices through the development of a leali between the linewires and the ground.

.it still further object of my invention is to obtain a reversal of thecurrent through the receiving` devices for each stroke of a signal, suchreversal to be substantially coincident and co-extensive with theincrease in the current while requiring but a single series loop for thetransmitting devices and a single series loop for the receiving`devices; both of said loops being1 normally fed from the same battery inseries with each other, but said loops being connected in parallel witheach other during1 the transmission of signals.

itiy present invention is in the nature of an improvement over thatshown in my prior patent dated May 20, 1913, No. lttl, and also overthat shown in my co-pending application Serial No. 808,572.

ln both said patent and said application l have shown a type ofsignaling1 system in which three current paths are provided, in two ofwhich paths are connected comparatively high resistances and in thethird ot Specification of Letters Patent.

Patented Apr. t3, i915..

serial No. essere.

which paths is connected a loop including a plurality of signalreceiving devices ol' comparatively loiY resistance, a source of currentbeing supplied and circuit changing mechanism being provided whereby thepaths may be connected in series or in parallel with each other. ln mysaid foregoing patent there is shown but one circuit changing device andsuitable circuit connections and two resistances adapted to be locatednear the source of energy, wiile a loop adapted to communicate withsignal receiving devices at distant points and to include said devicesin series with each other was provided, which loop is herein referred toas a receiving' device loop. ln my said copending` application a numberof circuit changing devices were provided, each capable of changing,`the circuit relations ot the three current paths from series toparallel, and each controlled by a signal transmitting mechanism, but inemploying the system shown in my said co-pending application, it isnecessary to equip each transmitting, device with a circuit changingdevice having` two sets ot circuit controllers, and it is furthernecessary to provide tour condu ctors for connecting1 suchtra-nsmittingl devices, between which conductors the circuitcontrolling' contacts of the various transmitting devices are connectedin parallel, and on account of such parallel connection, the conditionof the contacting` surfaces of these circuit controllers .is not underconstant test, and not only is a comparatively expensive system ofwiring` required, but extra heavy circuit controlling contacts arerequired for each transmitting device, on account of their being calledupon to both malte and break the eXtra heavy current used in si gnaling.

ln my present invention but one set of circuit controllers is providedtor each transmitting device, and these circuit controllers are arrangedin series in a simple loop which is herein referred to as atransmitting' device loop, a suitable circuit changino; device being;`provided at a convenient point having a magnet so connected with thetransmitting device loop as to be controlled by all of the tranemitting`devices, and to, in turn, control circuit changing mechanism for threeloops, so that said loops may be connected with the source of currenteither in series with each other or in parallel with cach other, by saidcircuit changing 11a device. Thus the circuit controllers of the varioustransmitting devices are merely called upon to break the Vweak currentwhich passes over the line when the three loops are connected to thesource of current in series with each other, and when acting to closethe circuit are only called upon to carry such current as will passthrough the transmitting loop and its resistance when said loop isconnected across the terminals of the source of current. The third loopcontrolled by the circuit changing device is of relativelyhighresistance and is provided to enable the other two loops to besubjected to proper tests by the use of a comparatively weak currentwhen such loops are not connected in parallel with each other, and thisthird loop is herein referred to as a continuity loop.

1n order that my invention may be better understood, 1 show in thedrawing annexed to and forming part of this specification a signalingsystem embodying my invention, but I do not limit myself to theparticular arrangement shown, as it is evident that features of myinvention are adapted for use either separately or in combination witheach other, and the particular descriptions hereinafter contained of thetypical system shown in annexed drawing are given for the clearerillustration of my invention, and many changes in construction andarrangement and insertion or omission of parts may be made withoutdeparting from the spirit of my invention.

1n the accompanying drawing 1 is the source of current, one terminal ofwhich is connected through wire 2 to contact 102, and the other terminalof which is connected through the wire 18 to contact 103.

rlhe transmitting loop comprising the wires 2, 3, 4, 5, 6 and 7 ,isconnected between Contact 102 and contact 106 and includes resistance 9connected between the wires 2 and 3, winding of magnetically controlledcircuit changing device 10 ecnnected between wires 3 and 4, circuitcontrolling contacts 11, 12 and 13 connected between wires 4 and 5, 5and 6, and 6 and 7, respectively, which contacts are shown as formingpart of transmitting devices A, B and C, the remaining structure ofwhich devices is represented by the characteristic signal wheels 14, 15and 16.

The continuity loop comprising the wires 18, 19 and 20 is connectedbetween contacts 103 'and 105and said loop serially includes thecontinuity loop resistance 21 connected between wires 18 and 19 and th'ewinding of ground test relay 22 connected between wires 19 and 20.

The receiving loop is connected between contacts 105 and 106, saidreceiving loop consisting of the wires 23, 24, 25, 26, 27 and 28, andsaid loop serially including the winding of the receiving devices shownby characteristic representations of gongs or bells, D, E, F, G and H,whose windings are connected between the wires 23 and 24, 24 and 25, 25and 26, 26 and 27, and 27 and 28, respectively.

The circuit changing device 10 is shown as having magnet 101 andcontacts 102, 103 and 104 controlled thereby, said contacts beingadapted to connect with the contacts 105, 106 and 107, respectively.

A typical local signal consisting of the bell 30 and battery 31 is shownconnected to the contacts 104 and 107 associated with the circuitchanging device 10, to be suitably controlled thereby, and said localsignal is shown as also being suitably controlled by the ground testrelay 22.

It is desirable that the local signal should be operated at least assoon as, and preferably a little in advance of, the contacts 102 and103, and 105 and 106 oi the circuit changing device 10 so that the localsignal will sound whenever these contacts or either of them cometogether.

rlhe circuit controlling contacts of the transmitting devices arearranged to stand normally closed, and the magnet of the circuitchanging device 10 is thus normally energized and the connection betweencontacts 102, 103 and 104 and contacts 105, 106 and 107, respectively,is thereby interrupted. lhile said contacts are separated, the path ofcurrent is from the source 1 through wires 2, 2, transmitting loopresistance 9, wire 3, winding of circuit changing device 10, wire 4,circuit controlling contacts 11, wire 5, circuit controlling contacts12, wire 6, circuit controlling contacts 13, wire 7 to contact 106,thence through wire 28, winding of receiving device H, wire 27, windingof receiving device G, wire 26, winding of receiving device F, wire 25,winding of receiving device E, wire 24, winding of receiving device Dand wire 23 to contact 105, thence through wire 20, winding of groundtest relay 22, wire 19, continuity loop resistance 21 and wire 18 tocontact 103, thence through wire 18 to other terminal oi currentsource 1. Vhile the circuit conditions just described are maintained,the contacts of relay 22 will be held open, and the cont-acts 104 and107 of circuit changing device 10 being also held open as alreadydescribed, the local signal device 30 will be silent.

The combined resistance of the receiving devices D, E, F, G and H, addedto the rcisistances 9 and 21, as well as the resistance of the magnet101 of the circuit changing device 10 and the relay 22, is such that thecurrent flow through the path including the transmitting, receiving andcontinuity loops when connected in series as just described, will not besufiicient to cause the l l L1 insane? magnets provided in the alarmreceiving devices to actuate their armatures, although said current issu licient to cause the magnet of the circuit changing device and groundtest relay 2a to retain their respective armatures. lit', under theseconditions, one of the signal transmitting devices be operated, lic"example, the device at station il, the rotation oiI Wheel la Will permitthe separat-ion of contacts 11, whereupon the rloiv of current throughthe path just described will be interrupted and the circuit changingdevice 10 will thereupon act to close its contacts and thereby connectthe Vtransmitting loop, receiving loop and continuit7 loop in parallelWith each other, While leaving them connected With the source olicurrent 1. The current paths 'from the source 1 will then be as followsFrom one terminal ol said source through the Wire 2 to the contact 102to contact 105 from which tivo current paths will be provided, one oiwhich Will be through the continuity loop and the other of which will hethrough the receiving` loop to the contact 103, thence to the otherterminal of the current source 1 through the vvire 18.

The current path between contact 105 and contact 103 through thereceiving loop will be as follows:lhrough Wire 23, Winding of receivingdevice D, Wire 24e, winding o5 receiving device lll, Wire 25, Winding ofreceiving device ll, Wire 26, Winding of receiving device G, Wire 27,Winding ol' recci ving device ll, and Wire 28 to contact 106 uhich ivillbe touching contact 103.

.llhe path of current through the continuity loop will he from contact105 through Wire 520, Winding of ground test relay 92, Wire 10,resistance 21, and Wire 18 to contact 10B.

lllhenever the receiving and continuity loops are connected in parallelthrough the path just described, the transmitting loop will als heconnected to the source 1 through 'the contact 100 in addition to itspermanent connection at the contact 102, but no current will liovvthrough the transmitting loop as long as the contacts 11 remain open,but upon the closing of the contacts l1` a third current path throughthe transmitti1 -g loop will he established from the sourccl lthroughivires 2, il, transmitting loop resistance 0, ivire 3, magnet 101, wired, ciiicuit controlling contacts 11, vvire 5, circuit controllingcontacts 12, ivire 0, circuit controlling contacts 13, and wire 7 tocontact 100, thence through contact 108 and vire 18 to the otherterminal olE the current source 1.

llpon the establishment of the current iloiv through the transmittingloop resulting from such closure oit' the circuit controlling contacts11, the circuit changing device l0 acts to break connection hetiveen itsvarious contacts and thus change the circuit relations of the threeloops from parallel to series, whereupon the current path would be firstdescribed.

During the time that the receiving loop ivas directly connected to thesource of current through the engagement ot contacts 109J and 103 withcontacts 105 and 106, the cur'ent tloiv through the inagnets of therecei. ng devices ivould be limited only hy the resistance ci? themagnets or said devices and the conductors connecting them directly withthe source olI current through th contacts of the circuit changingdevice 10. rlhus, the current tloiv through these devices would begreatly increased, and it Will be -noted that in changing the circuitrelations of the three loops from series to parallel, the direction ofthe current llo v in 'the receiving loop is always reversed, as, whenthe loops are connected in series relation, the current path from theterminal oi the current source connected by Wire 2 is through thetransmitting loop to contact 100. and thence through ivire E28 ot thereceiving loop, While the current path when the loops are connected inparallel is from the terminal of the current source connected by Wire 18through contacts 103 and 106 to .Wire 28 of the receiving loop.

lt will thus ce seen that the magnets of the receiving devices will healternately subjected to a heavy tloivo'l current in one direction inresponse to breaks .in the transmitting loog and to a ivealr iloiv ofcurrent in the opposite direction during the closed circuit condition otthe transmitting loop, thus assuring eilective operation of theniagnetic mechanism oli' the receiving devices, not only through theapplication oli the strong current for the strokes ot a signal, but alsothrough the use olE a Weak reversed current between strokes, having atendency to demagnetize or vercome residual inagnetism in theelectro-magnetic structures oit the receiving devices.

his the rotation of the si gual ivheel 1lwill first produce tivo brealsand then, after a suitable interval, produce Vtour hrealrs in thetransmitting loop., it is evident that the signal Zwei ivill heeiliectively indicated oy the receiving devices and during thetransmission of this signal the local signal 30 ivill sound in responseto the breaks in the transmitting loop, but upon the completion oit therotation ot the signal Wheel 111 and the consequent closing oit thetransmitting loop, the local signal rvill he silenced through thedisengagement of the contacts 1 0-l and 107 upon the final energizationo the magnet 101 of the circuit changing device. lt is desirable thatthe resistances 9 and 21, the circuit changing device 10, ground testrela;7 22, local signals 30 and hattery 31 should be located in closeproximity to each cther,'so that the wires 18, 19 and 20 and the wiresconnecting the local signal device may be as short as possible, and, infact, may be in the form of bus bars or heavy conductors mounted upon aterminal hoard or similar structure, so Vthat these conductors will beprotected as far as possible Yfrom rupture or grounding.

lr" it is desired to practically eliminate the sparking between contacts102 and 103 and the contacts 105 and 106, a suitable condenser 32 may beconnected at any convenient point on either the wire 7 or the wire 28and either the wire 20 or the wire 23.

ln the event of an accidental break in the transmitting loop, it isevident that the magnet 101 of the circuit changing device 10 willimmediately fail and the contacts 102, 103 and 104 will connect with thecontacts 105, 100 and 107, respectively, thus causing the local signalto sound continuously and subjecting the devices in the receiving loopto heavy signaling current.

ln the event of an accidental break in the receiving loop, the magnet101 of the circuit changing device 10 will likewise fail, but upon thecontact 103 connecting with the contact 100, current will bere-established through the transmitting loop and thereupon againenergize magnet 101, whereupon a vibrating action ot the contacts 102,103 and 10lV willibe set up, and during the periods when said contactsconnect with Vtheir cooperating contacts 105, 10G and 107, the localsignal will be sounded as the result of the connection between contacts104 and 107, and during such periods as these contacts are apart,leaving the continuity loop in series relation with the receiving loop,it is evident that the accidental break in the receiving loop will causethe magnet of relay 22 to fail, and thus the circuit through localsignal 30 will be maintained almost continuously, being alternatelyclosed through the action of relay 22 and circuit changing device 10. ilVith proper construction of parts, the chance of an accidental break inthe continuity loop may be reduced to a minimum, as hereinbeferesuggested, but should a Y break occur in this loop the relay 22 willimmediately act tc cause the local signal to sound while the circuitchanging device 10 will vibrate as already explained.

Should the connection between current source 1 and contacts 102 or 103be accidentally broken, both the circuit changing device 10 and theground test relay 22 will act to cause the local signal 30 to sound.

ln signaling systems such as herein described, it is frequentlydesirable that means should be provided whereby an accidental groundconnection may be instantly indicated, and while keeping the circuitunder test for this purpose, it is also desirable that no condition willbe produced which would result in rendering the receiving devicesunresponsive to signaling circuit changes. For the purpose of applyingsuch a test, a ground connection is provided in the signaling system ata point between the terminals of the resistance 21, and while thisground connection may be applied at various points between the terminaloil the resistance 21 connected to wire 18 and the terminal connected towire 19, the most desirable results will be obtained if this groundconnection is applied at a point between the terminal of the ground testrelay 22 which is connected to the wire 20 and the terminal of theresistance 21 which is connected to the wire 18 which is electricallymidway between said points.

rThe advantage obtained through applying the ground connection at apoint electrically midway between wire 18 and wire 20 will be manifestwhen it is considered that if the ground connection was applied directlyto wire 18 and an accidental connection developed between wire 23 andthe ground, if the circuit changing device 10 acted to close itscontacts while such accidental ground connection existed, the currentsource 1 would be short-circuited through the iollowing path: Fromsource 1 through wire 2', contact 102, contact 105, wire 23 toaccidental connection between said wire and ground, thence to permanentconnection between wire 18 and ground, through wire 1 to contact 103,thence through wire 18 to other terminal of the source of current.

On the other hand, if the resistance of the winding of ground test relay22 is comparatively low and the permanent ground connection is appliedto wire 19, in the event of an accidental connection between wire 28 andthe ground, the winding of ground test relay 22 would be connecteddirectly across the source of current through the following path(assuming, as before, that the circuit changing device 10 has acted toclose its contacts) From current source 1 through wire 2, contact 102,contact 105, wire 20, winding of ground test relay 22 to permanentground connection applied to wire 10, thence through the accidentalground connection to wire 28 and through wire 28 to contact 106, contact103 and through wire 18 to other terminal of current source 1.

It is evident `from the foregoing that the resistance between groundconnection 33 and either the wire 18 or the wire 20 must be such as willprevent an excessive iiow of current as the result of any accidentalground, regardless of whether the loops are connected in series or inparallel.

With the ground connection thus established, it is evident that thedevelopment of a connection, as, for example, between the wire 25 andthe ground, while the transof the resistance 21 between the ground con-;

nection and the wire 19 and also shunt the ground test relay 22 andreceiving devices D and E, thus causing local signal 30 to sound throughthe closing oi the contacts of ground test relay 22, but leaving thesignaling system in operative condition in that the circuit changingdevice 10 will remain responsive to the transmitting devices A, B and Cand the signal receiving devices D and E will remain responsive to theconnection of the three loops in parallel instead of series, as theground connection willI merely aiiord a high resistance path in parallelwith these signaling devices and not materially decrease the currentilow therethrough, as the fall of potential between contact 105 and thewire 25 will be only that incidental to the iiow of the heavy signalingcurrent through receiving devices D and it, while the resistance of theportion oi" resistance 21 and the relay 22 in parallel with thesedevices would be much greater than the resistance of all of thereceiving devices.

it a connection should develop between wire 28 and the ground, the lowof current during closures of contacts 102 and 103 with contacts 105 and106 through the receiving loop would not be noticeably decreased, but afourth loop would, in effect, be established as follows z-mhetransmitting loop would remain unchanged between contacts 102 and 103via contact 106. lThe receiving loop would remain unchanged betweencontacts 105 and 106. A portion of the continuity loop would be shunted,the current path from contact 103 through wire 18H and the portion ofresistance 21 between the ground connection and wire 18 being inparallel with a path from contact 103, throughcontact 106 and wire 2S toacci- ,dental ground, thence through ground connection to point inresistance 21 connected thereto. From this point the current flow wouldbe through the portion of re- `sistance 21 between the ground connection33 and the wire 19, wire 19, the winding of relay 22, wire 20, throughcontact 105 to Contact 102. a

1n the use oithis system, the action `oli the circuit changing device ismade more positive and effective through the fact that when thetransmitting loop is closed while the armature of this device is inretracted position, the current flow through the magnet of the circuitchanging device will be much greater than normal until the armaturemoves far enough toward attracted position to open the contactscontrolled thereby, and although the current direction through thereceiving loop is reversed for each impulse of a signal, the currentflow through the transmitting loop is at all times in one direction.

Such amount of resistance should be distributed between the resistance 9and magnet 101, resistance 21 and magnet 22 as to cut the currentliowing through the loops when in series down to a point which willbarely hold the armature of ground test relay 22 and the armature ofcircuit changing device 10 in attracted position, but insuihcient tomove either of said armatures to attracted position, so that a veryslight decrease in the electro-motive orce of the eurrent source 1 willbe promptly indicated by the failure of one or both of these devices, asit is evident that whenever the circuit changing device 10 acts to groupthe loops in parallel, the current flow through either the continuityloop or the transmitting loop when closed will be so increased as to etfectively energize these magnets.

As the current flow through the continuity loop during signaling periodsis practically wasted, the resistance of this loop should preferably berelatively high and the resistance of the transmitting loop should berelatively low, in comparison with the resistance of the continuityloop, while relatively high in comparison with the resistance of thereceiving loop.

As an example of a desirable relation of resistances for the variousloops in the system shown, it may be assumed: That the source of current1 maintains a constant potential of' 50 volts, while the receivingdevices D, E, F, Gr and H are direct acting bells operable at greatesteiliciency at a current flow of one (1) ampere, and having such windingthat the resistance of the receiving loop will be about ohms, thesegongs being unresponsive to a current flow of 10 milliamperes. That thecircuit changing device 10 is sowound as to be adapted for mosteliective operation to break its contacts when energized by a currentstrength of 100 milliamperes, and to hold its contacts apart at acurrent strength of 10 milliamperes, the resistance 9 being such as tobring the total resistance of the transmitting loop to 500 ohms. Thatthe ground test relay 22 is adapted to attract and retain its armatureat a current flow through its magnet windings of 11 milliamperes and toretain its armature at a current flow of 10 milliamperes, the resistance21 being such that the entire resistance of the continuity loop is 41450ohms. Employing these resistances, it is evident that when the threeloops are in series, the total resistance between the terminals of thecurrent source 1 will be about 5000 ohms, and with the assumed voltageof 50 volts a normal test current of 10 milliamperes will pass, thusmaintaining the armatures of the circuit changing device 10 and groundtest relay 22 in attracted position.

Ylso

It is also evident that upon the circuit changing device 10 acting toclose the contacts controlled thereby, the current lloiv through'thereceiving loop will be reversed in direction and increasedto a strengthof l ampere, but the current flow through the continuity loop vvill beneither reversed nor greatly increased, but will merely rise to a valuebetvveen ll and l2 milliamperes; but When thetransmitting loop is againclosed, the current therethrough Will immediately rise to a value ofabout 100 milliamperes and continue at that strength until the circuitchanging device 10 has acted to connect the 'three loops in series whenthe current fioW through all of said loops will return to 'normalstrength of about l() milliamperes.

The foregoing resistances and operating values are only assumed forpurposes of illustration and may be varied at will to adapt my systemfor use .vith any desired arrangement of relays, receiving devices, orcircuit changing conditions, vand the ground test connection and relaymay or may'not be employed, as desired.

- l/Vhat I claim is 1. In a signaling circuit, a plurality oftransmitting devices in one loop thereof, a plurality of receivingdevices in a second loop thereof, said loops being normally connected inseries With each other, and means controlled by each and every one ofsaid transmitting devices for connecting said loops in multiple Witheachother.

2. Asignaling system comprising a circuit having in series therein asource of current, a plurality of transmitting devices each adapted tobreak the current flow therethrough, a magnet responsive to such breaksof said current flow, and a plurality of receiving devices, incombination with means controlled by said magnet for causing anoperatively abnormal current flow through said receiving devices duringeach of said interruptions in the current fiovv through saidtransmitting devices.

3. In a signaling circuit, a plurality of transmitting devices in oneloop thereof, a

plurality of receiving devices in a second loop thereof, said loopsbeing normally connected in series With each other, and means-controlled by any transmitting device for connecting said loops inmultiple with each other, and for reversing the current through the loopincluding said receiving devices.

t. In a signaling circuit, a plurality-of transmitting devices and arelay in one loop thereof, said relay being responsive to the signals ofsaid transmitting devices, a plurality of receiving devicesin a secondloop thereof,said loops being normally connected in series With eachother, and means con'- trolled by said relay for connecting the ends ofsaid loops in multiple with each other to the current source.

5. In a signaling circuit, a plurality of transmitting devices and arelay in one loop thereof, said relay being responsive to the operationof said transmitting devices, a plurality of receiving devices in asecond loop thereof, said loops being normally connected in series witheach other, and means controlled by said relay for reversing the currentthrough the loop including said receiving devices.

6. In a signaling circuit, a plurality of transmitting devices and arelay in one loop thereof, said relay being responsive to the operationof Vsaid transmitting devices, a plurality of receiving devices in asecond loop thereof, said loops being normally connected in series witheach other, and means controlled by said relay for connecting said loopsin multiple with each other and for reversing the current through theloop including said receiving devices.

7. In a signaling circuit, a plurality of transmitting devices in oneloop thereof, a plurality of receiving devices in a second loop thereof,a resistance in a third loop thereof, said loops being normallyconnected in series with each other, and means controlled by anytransmitting device for connecting said loops in multiple with eachother.

8. In a signaling circuit, a plurality of transmiting devices in oneloop thereof, a plurality of receiving devices in a second loop thereof,a resistance in a third loop thereof, said loops being normallyconnected in series With each other, and means controlled by anytransmitting device for reversing the current through the loop includingsaid receiving devices.

9. In a signaling circuit, a plurality of transmitting devices in oneloop thereof, a plurality of receiving devices in a second loop thereof,a resistance in a third loop thereof, said loops being normallyconnected in series With each other, and means controlled by anytransmitting device for con necting said loops in multiple with eachother, and for reversing the current through the loop including saidreceiving devices.

l0. In a signaling circuit, a plurality of transmitting devices and arelay in one loop thereof, said relay being responsive to the operationof said transmitting devices, a plurality of receiving devices in asecond loop thereof, a resistance in a third loop thereof, said loopsbeing normally connected in series with each other, and means controlledby said relay for connecting said loops in multiple with each other.

l1. In a signaling circuit, plurality of transmitting devices and arelay in one loop thereof, said relay being responsive to the operationof said transmitting devices, a plurality of receiving devices in asecond loop thereof, a resistance in a third loop thereof, said loopsbeing normally connected in series with each other, and means con-atrolled by said relay for reversing the current through the loopincluding said receiving devices.

l2. lln a signaling circuit, a plurality of transmitting devices and arelay in one loop thereof, said relay being responsive to the operationof said transmitting devices, a plurality of receiving devices in asecond loop thereof, a resistance in a third loop thereof, said loopsbeing normally connected in series with each other, and means controlledby said relay for connecting said loops in multiple with each other forreversing the current through the loop including said receiving devices.

13. ln a signaling circuit, a plurality of transmitting devices and arelay in one loop thereof, said relay being responsive to the operationof said transmitting devices, a plurality of receiving devices in asecond loop thereof, a resistance and a second relay in a third loopthereof, a ground connection between the terminals of said loop, saidloops being normally connected in series with each other, local signalmechanism controlled by both said relays, and means controlled by saidfirst named relay for operatively altering the current through saidreceiving devices.

ll. ln aA signaling circuit, a plurality of transmitting devices and aresistance and a relay in one loop thereof, said relay being responsiveto the operation of said transmitting devices, a plurality of receivingdevices in a second loop thereof, a second resistance and second relayin a third loop thereof, a ground connection between the terminals .ofsaid second resistance, said loops being normally connected in serieswith each other, local signal mechanism con trolled by both said relays,and means conJ trolled by said irst named relay for operatively alteringthe currentY through said receiving devices.

l5. it signal system comprising a circuit having therein signaltransmitting devices and signal receiving devices, a source of current,a ground connection, two normally energized relays, two resistances, oneresistance and one of said relays being connected between one terminalof said source of current and one wire of the signal circuit, the secondresistance having one terminal connected to the other terminal of thesource of current, a portion of its resistance between said terminal andsaid ground connection, and its other terminal connected to one terminalof the other of said relays, the other terminal of said second relaybeing connected to another wire of the signal circuit, local signalmechanism controlled by said relays, and means controlled by anytransmitting device for connecting said resistances in multiple witheach other and with the receiving devices, and for reversing the currentthrough said receiving devices.

1G. A signal system comprising a circuit having therein signaltransmitting devices and signal receiving devices, a source of current,a ground connection, two normally energized relays, two resistances, oneresistance and one of said relays being connected between one terminalof said source of cur- '7 17. A, signal system comprising a circuit lhaving therein signal transmitting devices and signal receiving devices,a source of current, a ground connectiomtwo normally energized relays,two resistances, one resistance and one of said relays being connectedf" between one terminal of said source of current andV one wire of thesignal circuit, the second resistance having one terminal connected tothe other terminal of the source of said terminal and said groundconnection, and its other terminal connected to one terminal of theother of said relays, the other terminal of said second rela-y beingconnected to another wire of the signal circuit, local signal mechanismcontrolled by said relays, and means controlled by Vany transmittingdevice for reversing the current through said receiving devices.

18. A signal system comprising a circuit having thereinvsignaltransmitting devices current, a portion of its resistance between andsignal receiving devices, a source of current, a normally energizedrelay, two resistances, one resistance and said relay being connectedbetween one terminal of said source of current and one wire of thesignal circuit, said relay being responsive to the operation of saidtransmitting devices, the second resistance having one terminalconnected to the other terminal of the source of current and its otherterminal connected to another wire of the signal circuit, and meanscontrolled by said relay for so connecting said resistances in multiplewith each other and with the receiving devices, as to reverse thecurrent through said receiving devices.V

19. A signal system comprising a circuit having therein signaltransmitting devices and signal receiving devices, a source of current,a normally energized relay, two resistances, one resistance and saidrelay being connected betvveen one terminal of said source of currentand one Wire of the signal circuit, said relay being responsive to theoperation of said transmitting devices, the second resistance having oneterminal connected to the other terminal of the source oi' current andits other terminal connected to another Wire of the signal circuit, andmeans controlled by said relay for connecting said resistances inmultiple vvith each other and With the receiving devices.

20. A signal system comprising a circuit having therein signaltransmitting devices and signal receiving devices, a source of current,a normally energized relay, tWo resistances, one resistance and saidrelay being connected between one terminal of said source of current andone Wire of the signal circuit, said relayv being responsive to theoperation of said transmitting devices, the second resistance having oneterminal connected to the other terminal of the source of current andits other terminal connected to another Wire of the signal circuit, andmeans controlled by said relay for reversing the current through saidreceiving devices.

2l. A signaling system comprising a circuit having in series therein asource ot current, a plurality of receiving devices having a relativelylow total resistance, a plurality of transmitting devices, a relayresponsive to the operation ot said transmitting devices, and avresistanceWhose combined resistance is relatively high in' comparisonwith the resistance of the receiving devices, and a second resistancerelatively high in comparison With the combined resistance ot thetransmitting devices, relay and Iii-st named resistance, and meanscontrolled by the relay or operatively altering the current through saidreceiving` devices.

22. In a signaling circuit', a plurality of transmitting devices and arelay in one loop thereof, said relay being responsive to the operationof said transmitting devices, a

plurality of receiving devices in a second loop thereof, a resistance ina third loop thereof, said loops being normally connected in series witheach other, the resistance of said first named loop being relativelyhigh in comparison with the resistance of said second loop, and beingrelatively low in comparison withthe resistance of said third loop, andmeans controlled by said relay for operatively altering the currentthrough said receiving devices.

Q3. A signaling system comprising a circuit having in series therein asource of cui rent, a plurality of transmitting devices, a relayresponsive to the operation olf said transmitting devices, and a pluality of rcceiving devices, and means controlled by the relay forconnecting that portion oit the circuit including said receiving devicesdirectly to the terminals oit said source ot current.

Y 24. A signaling system comprising a circuit having in series therein asource of current, a resistance, a plurality oi transmitting devices, arelay responsive to the operation of said transmitting devices, and aplurality of receiving devices, and means controlled by the relay itorconnecting said receiving devices in multiple with said resistance.

25. A signaling system cmnprising a cir cuit having in series therein asource of current, a resistance, a plurality ot transmitting devices, arelay responsive to the operation of said transmitting devices, and aplurality of receiving devices, and means controlled by the relay forreversing the current through said receiving devices, and for connectingsaid receiving devices in multiple with said resistance.

ln witness whereof, l hereunto subscribe my name, this 16th day ot'Mray, A. D., 1914-.

CLARENCE ll. gllAGll. lVitnesses:

C. M. CoNNnn'roN, lV. T. KENDALL BROWN.

l Copies of this patent may be obtained for ve cents each, by addressingthe Commissioner of Patents,

Washington, I). C.

